How to Design a Scalable Mail Notification System

I just Came across this requirement, the Requirement is Pretty Simple

1)Notification mail need to be sent to n Users at regular intervals Based on a Calendar Events. (Like 1 week before a Event).Notifications can be of N Types.

2)There will be N Countries(Users) who get this events at different intervals(some for a Quarter some monthly defined in a table)

3)we need to Switch on and off this Notifications for each Country based on request (Like Country A will say send Type 1 notifications not all)

4)Now the fun part I need to Integrate this notification to the .Net Web Application like Facebook shows on logging in.

I would like to know what pattern(.net and database) will fit this situation.I want to build a centralized Notification center.Used for Mail Service and Web App

My Current thought is to implement a new Table which will be having the Country Notification Allowed . Like Country A --> Notification Type 3

Based on this will send the Notifications in Service. once notification is sent i will log the Notification in a Logging Table. This Table will be used to show notification to the user when he logs in Web App.

Please suggest how can i design this .